This is a wavelength tunable fiber laser, packaged in a module. It use SM single-mode fiber, PM polarization-maintaining fiber can be customized. It controlled by software. If the software is opened, the Portlist is blank, and COM** cannot be found. Please check whether USB port driver on your computer is working properly. The adjustable wavelength light source is shipped with a power adapter and a data cable connected to the computer. Let's check it now.